2 University of Michigan 



Haplotype, — Uranidea qidescens DeKay {^Coitus gracilis Heckel). 

 Cottopsis Girard, Proc. Boston Soc. Nat. Hist., 3, 1850, p. 303; 

 Smiths. Contr. Knowl., 3, 1851, p. 61. 

 Orthotype, — Cottus aspcr Richardson. 



Potamocotttis Gill, Proc. Boston Soc. Nat. Hist., 8, 1861, p. 40. 

 Logotype, — Cottus puncttilatus Gill. 



Tauridea Jordan and Rice, Man. Vert. E. U. S., Ed. 2, 1878, p. 255. 

 Orthotype, — Cottopsis ricei Nelson. 



With the exception of Cottus {Tauridea) ricei of the 

 Great Lakes, the numerous American species of Cottus ap- 

 parently present no characters by which they may be satisfac- 

 torily grouped either generically or subgenerically. Two char- 

 acters have been so used by atithors in general: the develop- 

 ment of palatine teeth, and the number of rays in the pelvic 

 fin. These two features are correlated neither with each other 

 nor with other characters, and both vary widely within ob- 

 viously specihc limits. Consequently it appears that these 

 characters are not of the kind that prove of value in the dis- 

 tinction of natural groups. 



The palatine teeth vary widely, not only specifically, but 

 intraspecifically as well. In fact in several species these teeth 

 may be either present or absent. For example in Cottus asper 

 the palatine teeth, though usually well developed, are occasion- 

 ally obsolete.^ This species is the genotype of Cottopsis 

 Girard, a group based solely on the development of palatine 

 teeth.- In other cases the teeth on the palatines are occasional- 

 ly developed in those species in which the teeth are normally 

 lacking. 



The number of pelvic fin rays varies in Cottus gracilis, as 

 both Kendall and Gill have indicated {I.e.). Consequently both 



'Snyder, Bull. U. S. Bur. Fish., 27, 1907 (1908)^ p. 184. 



^ Potamocottus Gill is also based upon species with palatine teeth. The 

 earlier but inapplicable name Pegedictis Rafinesque (see Gill. /. c.) sometimes 

 altered to the correct orthography Pegedichthys, has been used by some authors, 

 including Jordan and itvermann (/. c), to designate those species having no 

 palatine teeth. 



